Synthesis of some new 3-coumaranone and coumarin derivatives as dual inhibitors of acetyl- and butyrylcholinesterase

Article abstract of DOI:10.1002/ardp.201300080

A novel series of coumarin and 3-coumaranone derivatives encompassing the phenacyl pyridinium moiety were synthesized and evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity using Ellman's method. All compounds presented inhibitory activity against both AChE and BuChE in the micromolar range. The molecular docking simulations revealed that all compounds were dual binding site inhibitors of AChE. A kinetic study was performed and the mechanism of enzyme inhibition was proved to be of mixed type. All compounds were tested for their antioxidant activity and no significant activity was observed.

Full text of DOI:10.1002/ardp.201300080

Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
577
Full Paper
Synthesis of Some New 3-Coumaranone and
Coumarin Derivatives as Dual Inhibitors of
Acetyl- and Butyrylcholinesterase
Masoumeh Alipour1, Mehdi Khoobi2, Hamid Nadri3, Amirhossein Sakhteman3, Alireza Moradi3,
Mehdi Ghandi1, Alireza Foroumadi2, and Abbas Shafiee2
1
School of Chemistry, University College of Science, University of Tehran, Tehran, Iran
Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center,
2
Tehran University of Medical Sciences, Tehran, Iran
Department of Medicinal Chemistry, Faculty of Pharmacy, Shahid Sadoughi University of Medical Sciences,
3
Yazd, Iran
A novel series of coumarin and 3-coumaranone derivatives encompassing the phenacyl pyridinium
moiety were synthesized and evaluated for their acetylcholinesterase (AChE) and butyryl-
cholinesterase (BuChE) inhibitory activity using Ellman’s method. All compounds presented
inhibitory activity against both AChE and BuChE in the micromolar range. The molecular
docking simulations revealed that all compounds were dual binding site inhibitors of AChE.
A kinetic study was performed and the mechanism of enzyme inhibition was proved to be of
mixed type. All compounds were tested for their antioxidant activity and no significant activity
was observed.
Keywords: Actylcholinesterase / Butyrylcholinesterase / Coumarin / 3-Coumaranone / Docking study / Phenacyl
pyridinium
Received: March 8, 2013; Revised: April 10, 2013; Accepted: April 12, 2013
DOI 10.1002/ardp.201300080
Introduction
site (PAS) and acylation site (ACS), respectively [1, 4, 5]. It was
revealed that the dual binding site inhibitors such as
donepezil exert better pharmacological profile rather than
propidium, a PAS binder inhibitor, or tacrin, an ACS binder
inhibitor [6, 7]. Therefore, designing dual binder inhibitors
can open a new way to combat AD. Based on these findings,
some bivalent ligands were synthesized using hybrid forma-
tion strategy such as tacrine-melatonin hybrids [8] and
tacrine-heteroaromatic group [9].
Butyrylcholinesterase (BuChE) is another important en-
zyme that co-localized with AChE in the brain with the lower
capacity for hydrolyzing of Ach [10, 11]. Recent studies
showed that the inhibition of BuChE along with AChE may
take an important role to improve AD’s symptoms. In fact
maintenance of the AChE/BuChE activity ratio in AD may be
vital to better management of the disease [12, 13]. Following
this rationale, several dual AChE-BuChE inhibitors were
synthesized and evaluated [14–16].
Acetylcholinesterase, is a key enzyme in the central nervous
system that is responsible for hydrolyzing acetylcholine (Ach)
particularly in cortex and hippocampus [1]. According to the
cholinergic hypothesis inhibition of AChE in the two
aforementioned parts of the brain can alleviate the sign
and symptoms of Alzheimer’s disease (AD) [2]. Donepezil,
rivastigmaine, galanthamine, and tacrine are the most known
and clinically applied AChE inhibitors that have been
approved by the United States Food and Drug Administration
(FDA) for treating AD [3]. There are two distinct ligand binding
sites in the narrow gorge of AChE that are located in the gorge
rim and at the bottom of the gorge named peripheral anionic
Correspondence: Dr. Abbas Shafiee, Department of Medicinal Chemis-
try, Faculty of Pharmacy and Pharmaceutical Sciences Research Center,
Tehran University of Medical Sciences, Tehran 14176, Iran
E-mail: ashafiee@ams.ac.ir
Coumarins (2-chromenone) as naturally occurring and
chemically synthesized compounds have attracted intense
Fax: þ98 21 66461178
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M. Alipour et al.
Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
interest in recent years. Coumarin derivatives have revealed Results and discussion
wide range of biological activities such as hepatoprotective,
anti-allergic, anti-HIV-1, anti-inflammatory, antifungal, anti-
microbial, antiasthmatic, anti-tumor, antiviral, anti-oxidant,
antinociceptive, anti-diabetic, antidepressant effects and
monoamine oxidase (MAO) inhibitory activity as well [17–
20]. Moreover, 3-coumaranones (3-benzofuranone) and their
analogs such as aurones are a family of heterocyclic
compounds which have a broad range of bioactivity and
predominantly have been used as potent anticholinesterase
inhibitors [21, 22]. The planarity and aromaticity of coumarin
and 3-coumaranone structure is the key feature that let
them interact easily with PAS through a possible p-p stacking.
In addition, presence of a positively charged group in the
vicinity of PAS binding part of the molecule makes the
compound more active via interaction with the anionic
subsite of AChE. Moreover, if this feature combines with the
aromaticity, an additional interaction with an aromatic
moiety of AChE will happen [23]. In accord with these
findings, several compounds with positively charged substi-
tuted nitrogen have been synthesized [24–27]. In view of the
above structural characteristics of the enzyme-inhibitors
interaction and to achieve dual binding site inhibitors,
some N-substituted heteroarylidene methyl pyridinium com-
pounds were designed and synthesized as potential dual
AChE-BuChE inhibitors. The designed structures encompass
three distinct parts with the ability to interact with different
active sites along the narrow gorge of the enzyme (Fig. 1). The
activity of the target compounds has been evaluated through
in vitro AChE-BuChE inhibition assay using Ellman’s colori-
metric method.
Chemistry
The synthesis of some coumarin and 3-coumaranone
derivatives comprising the phenacyl pyridinium moiety is
described in this work. The synthetic pathways for the
preparation of target compounds are illustrated in Schemes 1
and 2. Initially as previously reported, reaction of 2-hydroxy-3-
methoxybenzaldehyde 1 and ethyl acetoacetate 2 in the
presence of catalytic amount of piperidine yielded 8-methoxy-
3-acethyl coumarin 3 [28]. Compound 5 was prepared via an
aldol condensation of compound
3 and commercially
available pyridine-4-carbaldehyde 4. Different basic and acidic
media (p-toluenesulfonic acid (p-TsOH) in toluene, KOH or
gaseous HCl in ethanol, piperidine in ethanol or n-butanol)
were employed for preparing the latter compound, using both
thermal and microwave conditions. Under these conditions, a
mixture of geometric isomers with the excess amount of E-
isomer was formed, while under optimized condition
including piperidine in n-butanol and microwave irradiation,
only E-configuration was obtained (Scheme 1).
According to the coupling constant of 15–16 Hz between
the two olefinic protons, the E-configuration was assigned to
the exocyclic double bond. Finally, the target compounds
7a–e were obtained via the reaction of intermediate 5 with
various phenacyl halides in dry acetonitrile (Scheme 1).
Compound 10 was easily prepared through the reaction of
resorcinol 7 with chloroacetyl chloride 8 using AlCl3 as Lewis
acid followed by intramolecular cyclization with NaOH [21].
The alkylation of hydroxyl group of compound 10 using ethyl
iodide in dry N,N-dimethylformamide (DMF) gave compound
Figure 1. Designed structures as potential inhibitors of AChE and BuChE.
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3-Coumaranone and Coumarin Derivatives as ACE Inhibitors
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Scheme 1. Reagents and conditions: (a) piperidine, 50°C, 1 h; (b) piperidine, MW, 30 min; (c) phenacyl halide derivatives, dry acetonitrile,
r.t., 2–3 days.
11. The subsequent condensation of intermediate 11 with
pyridine-4-carbaldehyde 4 afforded the conjugate compound
12.
In the case of the compound 12, the best result was attained
in the presence of p-TsOH in dry toluene. The 13C NMR
chemical shift of the exocyclic olefinic carbon was around
113 ppm which was attributed to the Z-configuration [21, 29].
Finally, compounds 12 reacted with different phenacyl
halides 6 in dry acetonitrile to produce the target compounds
13a–e (Scheme 1).
Molecular modeling and ADME prediction
To get better insight to the interaction of tested compounds
and to develop preliminary structure activity relationship
(SAR), docking studies were performed using Autodock vina
1.1.1. Analysis of docking results revealed that all target
compounds exhibited dual binding mode but with slightly
different interactions with the receptor. The compounds are
oriented towards the gorge of the enzyme in two different
ways. The coumarin derivatives 7 are more prone to the
catalytic site while 3-coumaranone derivatives 13 are at the
Scheme 2. Reagents and conditions: (a) AlCl3, reflux, overnight; (b) NaOH 5%, 0°C to rt; (c) HCl 6 M; (d) ethyl iodide, anhydrous K2CO3, dry
DMF, 80°C, 2 h; (e) PTSA, reflux, 3 h; (f) 10% sodium hydrogen carbonate, 30–60 min; (g) phenacyl halide derivatives, dry acetonitrile, r.t.,
3–4 days.
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Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
vicinity of the PAS. The 3-coumaranone series 13 are well
superimposed at the midgorge recognition site of the enzyme
due to presence of a quaternary nitrogen in all compounds,
which gives them the ability to interact with Tyr330 through
formation of a p-cation bond. As illustrated in Fig. 2, all 3-
coumaranone derivatives 13 were superimposed in the gorge
of the enzyme except 13d. This can be explained by the more
polar property of the 3,4-dihydroxy phenacyl moiety which
makes it possible to interact with the more hydrophilic region
at the vicinity of the catalytic site. The complex was stabilized
via two hydrogen bond interactions with Glu199. It is feasible
for the longer molecule in coumarin derivatives 7 to stretch
out beyond the gorge and interact with Trp84 at the proximity
of the catalytic site via a p-p interaction (as depicted in Fig. 3).
Using PreADMET web-based application (http://preadmet.
bmdrc.org), different pharmacokinetic properties were pre-
dicted for all target compounds such as blood-brain barrier
(BBB) penetration activity, log D, percentage of human
intestinal absorption (HIA) and van der Waals surface area
of polar nitrogen and oxygen atoms (PSA and tPSA). The
predicted data are summarized in Table 1.
According to the table, all the target compounds exhibited
desirable ADME properties. All of them except for 13a, 13d,
13e, and 13f may be able to penetrate into the central nervous
system (CNS) and show CNS activity due to comprising
ꢀ
suitable ADME properties such as PSA < 60–70 A2 [30].
Biological activity
Ellman’s method was used to determine anticholinesterase
activity of new series of coumarin 7a–e and 3-coumaranone
13a–e derivatives. The activities of two series of compounds
against both acetylcholinesterase and butyrylcholinesterase
are summarized in Table 2. In order to investigate whether the
IC50 values are statistically different, one-way ANOVA
followed by Newman–Keuls post-test was performed and
the p-values <0.05 were considered as significant. Donepezil
hydrochloride was used as the reference drug for both target
enzymes.
Most of the compounds were active against acetylcholines-
terase in the range of 1.3 to 36 mM. It was observed that 3-
coumaranone derivatives were normally more potent agents
than coumarin analogs against acetylcholinesterase. On the
contrary, the compounds with no substituent at phenacyl
substructure showed similar activities as in compounds 7c
and 13c with IC50 values of 10 and 7.4 mM, respectively
(p > 0.05). This finding shows the role of substitution at
phenacyl part of the compounds. Based on the IC50 values of
coumarin derivatives against AChE, the order of activity for
substituents at phenacyl substructure was 4-F ꢁ 4-H > 4-
CH3 > 4-OCH3 > 4-Br. In this series the order of activity was
affected by both the electron withdrawing nature and the
lipophilicity of the substituents. Electron withdrawing group
with low lipophilic property is well tolerated at para position
as seen in compound 7d. In contrast substituents with more
electron donating property such as methyl and methoxy
decreased the activity via weakening the critical p-p interac-
tion with Trp84. Since the phenacyl group was oriented
towards a hydrophilic pocket composed of Gly441, Glu199,
His440, and Tyr130, the more lipophilic substituents at para
position were not well accommodated in such a lipophilic
pocket as in compound 7e having bromo substituent (Fig. 4).
In addition, coumarin derivatives 7 exhibited lower activity
against butyrylcholinesterase except in case of 7a with
methyl at phenacyl moiety as the most active compound in
this series (IC50 ¼ 8mM).
Figure 2. Superimpositions of the best-docked poses of com-
pounds 13a–e in the active site of AChE.
On the other hand, in 3-coumaranone series 13, all
substituents at para position of phenacyl led to an increase
in the activity of the target compounds compared to 13c with
no substituent. Based on docking studies insertion of an
Figure 3. Superimpositions of the best-docked poses of com-
pounds 7a–e in the AChE binding site.
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3-Coumaranone and Coumarin Derivatives as ACE Inhibitors
581
Table 1. In silico predicted ADME properties and molecular descriptors of the target compounds.
ꢀ
Compounds
R
Surface area (A2)
LogDc)
BBB penetration
C. brain/C. bloodd)
CNS absorption [38]
HIA %e)
PSAa)
tPSAb)
7a
7b
7c
7d
4-CH3
4-OCH3
H
32.14
34.64
32.14
32.14
32.14
45.7
45.7
45.7
45.7
81.89
45.7
60.39
69.62
60.39
60.39
60.39
73.55
73.55
73.55
73.55
114.01
73.55
39.97
1.3
0.64
0.37
0.48
0.57
0.73
0.097
0.1
0.11
0.085
0.015
0.082
0.19
Middle
Middle
Middle
Middle
Middle
Low
Middle
Middle
Low
97.46
97.48
97.42
97.43
98.41
97.56
97.61
97.61
97.81
95.55
97.64
97.95
0.77
0.82
0.95
1.6
1.14
0.79
0.65
2.02
0.33
1.44
2.6
4-F
7e
4-Br
4-CH3
4-F
13a
13b
13c
13d
13e
13f
H
2,4-Cl
3,4-OH
4-Br
–
Low
Low
Middle
Donepezil
18.57
a)
Polar surface area.
Topological polar surface area.
Calculated in pH 7.4.
The ratio of the compound concentration in brain and blood.
The percent of human intestinal absorption.
b)
c)
d)
e)
electron withdrawing group enhanced the p–p stacking
interactions between phenacyl and Phe330 as in case of 13b
(p < 0.001) and 13e (p < 0.01). The enhanced activity of
compound 13a compared to 13c (p < 0.001) with no
substituent could be attributed to
interaction between methyl and Trp84 (Fig. 5).
a
lipophilic CH–p
In compound 13d with two hydroxyl groups at meta and
para positions of phenacyl moiety a hydrogen bonding
network with the residues at the bottom of the binding site
might be responsible for the improved activity (Fig. 6).
The most active compound was compound 13b with fluoro
at para position of phenacyl moiety (IC50 ¼ 1.3 mM). All
compounds showed to be less selective inhibitors than the
reference drug donepzil hydrochloride. Meanwhile, the
compounds bearing 3-coumaranone moiety were normally
more selective than those with coumarin substructure. It
seems that the lower selectivity index of the target
compounds makes them promising dual inhibitors of
AChE/BuChE for future studies.
Table 2. AChE and BuChE inhibition data and their selectivity for
synthesized compounds 7a–e and 13a–e.
Compound
R
IC50 (mM)a),b)
Selectivity
for AChEc)
Kinetic study
AChE
BuChE
The kinetic study was done on the most active compound,
13b, and the compound was tested at three fixed concen-
trations including 1.96, 3.92, and 19.6 nM. For each concen-
tration, the initial velocity (V) of the substrate hydrolysis was
measured at four different substrate (S) concentrations in the
range of 0.137–0.689 mM. Subsequently, the reciprocal of
the initial velocity (1/V) versus the reciprocal of the substrate
concentration (1/S) was plotted. Based on the Lineweaver–Burk
plot depicted in Fig. 7, a pattern of increasing slopes and
intercepts with higher inhibitor concentrations was obtained.
This pattern was representing a mixed type inhibition for
the compounds of this series. The result of this study was in
accord with docking studies regarding the dual binding mode
of the target compounds.
7a
7b
7c
7d
4-CH3
4-OCH3
H
4-F
4-Br
4-CH3
4-F
H
3,4-Di(OH)
4-Br
13.5 ꢂ 0.78
21.0 ꢂ 1.2
10.0 ꢂ 0.29
8.2 ꢂ 0.17
36 ꢂ 1.9
8.0 ꢂ 0.22
34 ꢂ 1.6
0.6
1.6
4.3
5.1
1.4
20
12.1
3.2
7.2
10.3
384
43 ꢂ 2.3
42 ꢂ 3.1
7e
51 ꢂ 2.9
13a
13b
13c
13d
13e
Donepezil
1.4 ꢂ 0.12
1.3 ꢂ 0.04
7.4 ꢂ 0.13
3.7 ꢂ 0.69
3.0 ꢂ 0.24
28.0 ꢂ 1.4
15.8 ꢂ 0.85
23.5 ꢂ 1.1
26.7 ꢂ 1.5
31 ꢂ 1.9
–
0.014 ꢂ 0.003 5.38 ꢂ 0.17
a)
The concentration of inhibitor required to produce 50%
enzyme inhibition.
b)
Data are means of three independent experiments ꢂ SE.
c)
Selectivity for AChE ¼ IC50 (BuChE)/IC50 (AChE).
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Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
Figure 4. Interaction of compound 7e docked into the binding site of AChE. The hydrophobic bromo substituent of 7e is oriented toward a
hydrophilic pocket of active site.
Total antioxidant activity
compounds may be beneficial to treat AD symptoms. Thus, total
antioxidant activity of the final compounds was measured
using FRAP (ferric reducing antioxidant power) assay and FRAP
values of the target compounds are presented in Table 3. As it
Since oxidative stress proved to be a key feature of AD that is
determined by increased oxidative markers including DNA,
RNA, lipid, and protein oxidation [31, 32], using antioxidant
Figure 5. The interacting mode of compound 13a in the active site of AChE.
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Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
3-Coumaranone and Coumarin Derivatives as ACE Inhibitors
583
Figure 6. The interacting mode of compound 13d in the active site of AChE.
can be seen in the table, none of the compounds showed Conclusion
significant antioxidant activity in comparison to ascorbic acid
as reference drug, except for compounds 7b and 13d. The
considerable antioxidant activity of compound 7b and 13d
could be attributed to presence of methoxy group and catechol
group on phenacyl moiety, respectively.
A novel series of some coumarin and 3-coumaranone
derivatives linking to phenacyl pyridinium moiety were
designed as dual binding site cholinesterase inhibitors. The
synthesized compounds were tested in terms of their
inhibitory potency against both AChE and BuChE. The
spectrophotometric method of Ellman was used for AChE/
BuChE inhibitory activity. All synthesized compounds showed
to be moderately potent dual inhibitors of AChE and BuChE,
with IC50 values ranging in micromolar. Compound 13b was
subjected for kinetic study and it showed the mixed type of
Table 3. The antioxidant activities of the compounds 7a–e and
13a–e.
Compounds
FRAP-valuea)
7a
7b
7c
NA
159
NA
7d
NA
7e
NA
13a
NA
13b
NA
13c
NA
13d
13e
676
NA
Ascorbic acid
2975
Figure 7. Steady-state Lineweaver–Burk plot of compound 13b,
against acetylcholinesterase enzyme. The plot is based on the
reciprocal of initial velocity and reciprocal of substrate concentration
at increasing inhibitor concentrations.
NA, no activity.
a)
FRAP value is expressed as mmol Fe(II)/g.
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M. Alipour et al.
Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
inhibition toward the AChE. These results are in agreement
with the conclusions of docking studies in which all
target compounds interacted with both the CAS and PAS of
AChE.
chromatography using petroleum ether/ethyl acetate (70:30) as
the mobile phase to give the further pure product.
General procedure for the synthesis of (E)-4-(3-(8-
methoxy-2-oxo-2H-chromen-3-yl)-3-oxoprop-1-enyl)-1-(2-
oxo-2-phenylethyl)pyridinium halides 7a–e
Experimental
To a solution of (E)-8-methoxy-3-(3-(pyridin-4-yl)acryloyl)-2H-chro-
men-2-one 5 (1 mmol) in dry acetonitrile (7 mL), different
phenacyl halides 6 (1.2 equiv) and catalytic amount of KI were
added. The reaction mixture was stirred at room temperature for
2–3 days. Progress of the reaction was monitored by TLC. After
completion of the reaction, the solid was filtered off and washed
with acetonitrile to give compound 7. The solids were further
purified if needed by flash chromatography using chloroform/
methanol (99:1) as the mobile phase.
Chemistry
All commercially available reagents were purchased from Merck
AG, Aldrich or Acros Organics and used without further
purification. Column chromatography was carried out on silica
gel (70–230 mesh). TLC was conducted on silica gel 250 micron,
F254 plates. The 3-acetylcoumarin 3 and 6-ethoxybenzofuran-3
(2H)-one 11 were prepared by the reported methods [21, 28]. For
the synthesis of compounds 5 the experiments were performed
using a microwave oven (ETHOS 1600, Milestone) with a power of
600 W, specially designed for an organic synthesis and modified
with a condenser and mechanical stirrer. Melting points were
measured on a Kofler hot stage apparatus and are uncorrected.
The IR spectra were taken using Nicolet FT-IR Magna 550
spectrographs (KBr disks). Mass spectra of the products were
obtained with an HP (Agilent Technologies) 5937 mass selective
detector. 1H NMR spectra were recorded on a Varian 400 or Bruker
500 MHz NMR instruments. The atoms numbering of the target
compounds used for 1H NMR data are depicted in Fig. 8. The
chemical shifts (d) and coupling constants (J) are expressed in
parts per million and Hertz, respectively. The results of elemental
analyses (C, H, N) were within ꢂ0.4% of the calculated values.
(E)-4-(3-(8-Methoxy-2-oxo-2H-chromen-3-yl)-3-oxoprop-
1-enyl)-1-(2-oxo-2-p-tolylethyl)pyridinium bromide (7a)
Yield 75%, orange solid, mp 183–185°C, IR ymax/cmꢃ1 (KBr): 1760,
1
–
1716 and 1679 (C O), H NMR (DMSOd , 400 MHz), 9.02 (d, 2H, H -
–
6
a
pyridine, J ¼ 6.4 Hz), 8.82 (s, 1H, H4 coumarin), 8.54 (d, 2H, Hb-
pyridine, J ¼ 6.4 Hz), 8.15 (d, 1H, Hb vinylic, J ¼ 16.4 Hz), 7.97 (d,
2H phenyl, J ¼ 8.4 Hz), 7.87 (d, 1H, Ha vinylic, J ¼ 16.4 Hz), 7.55–
7.38 (m, 5H, 2H phenyl and H5,6,7 coumarin), 6.44 (s, 2H, –CH2Nþ),
3.95 (s, 3H, OMe), 2.45 (s, 3H, Me). EI-MS m/z (%) 440 (Mþ, 6), 439
(22), 320 (56), 119 (100), 91 (95). Anal. calcd. for C27H22BrNO5: C,
62.32; H, 4.26; N, 2.69. Found: C, 62.18; H, 4.51; N, 2.38.
(E)-4-(3-(8-Methoxy-2-oxo-2H-chromen-3-yl)-3-oxoprop-
1-enyl)-1-(2-(4-methoxyphenyl)-2-oxoethyl)pyridinium
Representative procedure for the preparation of 8-
methoxy-3-acetyl coumarin (3)
bromide (7b)
Yield 68%, yellow solid, mp 257–259°C, IR ymax/cmꢃ1 (KBr): 1755,
To a cold mixture of 2-hydroxy-3-methoxy benzaldehyde 1
(0.2 mol) and ethyl acetoacetate 2 (0.2 mol), a few drops of
piperidine were added by rapid stirring. The mixture was allowed
to warm to 50°C. When the reaction was finished (monitored by
TLC), the yellow solid was filtered off and subsequently washed
with ethanol and crystallized from water/ethanol (30:70) [28].
1
–
1717 and 1675 (C O), H NMR (DMSO-d , 400 MHz), 8.99 (d, 2H,
–
6
Ha-pyridine, J ¼ 6.4 Hz), 8.81 (s, 1H, H4 coumarin), 8.54 (d, 2H, Hb-
pyridine, J ¼ 6.4 Hz), 8.17 (d, 1H, Hb vinylic, J ¼ 16.4 Hz), 8.05
(d, 2H phenyl, J ¼ 8.0 Hz), 7.87 (d, 1H, Ha vinylic, J ¼ 16.4 Hz),
7.53–7.38 (m, H5,6,7 coumarin), 7.19 (d, 2H phenyl, J ¼ 8.0 Hz),
6.39 (s, 2H, –CH2Nþ), 3.96 (s, 3H, OMe), 3.90 (s, 3H, OMe). Anal.
calcd. for C27H22BrNO6: C, 60.46; H, 4.13; N, 2.61. Found: C, 60.17;
H, 4.38; N, 2.39.
Representative procedure for the preparation of (E)-8-
methoxy-3-(3-(pyridin-4-yl)acryloyl)-2H-chromen-2-one (5)
To a stirring mixture of 8-methoxy-3-acetyl coumarin 3 (1 mmol)
and pyridine-4-carbaldehyde 4 (1.2 mmol) in 3 mL n-butanol were
added catalytic amounts of piperidine (2 drops). The mixture was
irradiated with microwaves at 150°C for 30 min. After comple-
tion of the reactions, the mixture was cooled and the solid was
filtered off and washed with ethanol. The organic phase was
evaporated and the residue was purified by silica gel column
(E)-4-(3-(8-Methoxy-2-oxo-2H-chromen-3-yl)-3-oxoprop-
1-enyl)-1-(2-oxo-2-phenylethyl)pyridinium chloride (7c)
Yield 60%, orange solid, mp 189–191°C, IR ymax/cmꢃ1 (KBr): 1757,
1
–
1715 and 1681 (C O), H NMR (DMSO-d , 400 MHz), 9.03 (d, 2H,
–
6
Ha-pyridine, J ¼ 6.4 Hz), 8.83 (s, 1H, H4 coumarin), 8.55 (d, 2H,
Hb-pyridine, J ¼ 6.4 Hz), 8.18 (d, 1H, Hb vinylic, J ¼ 16.4 Hz), 8.08
Figure 8. The atoms numbering of the target compounds.
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Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
3-Coumaranone and Coumarin Derivatives as ACE Inhibitors
585
(d, 2H phenyl, J ¼ 7.2 Hz), 7.87 (d, 1H, Ha vinylic, J ¼ 16.0 Hz),
7.80 (t, 1H phenyl, J ¼ 7.2 Hz), 7.69 (d, 2H phenyl, J ¼ 7.2 Hz),
7.55–7.40 (m, H5,6,7 coumarin), 6.48 (s, 2H, –CH2Nþ), 3.96 (s, 3H,
OMe). EI-MS m/z (%) 426 (Mþ, 5), 425 (19), 320 (87), 307 (72), 105
(100), 77 (61). Anal. calcd. for C26H20ClNO5: C, 67.61; H, 4.36; N,
3.03. Found: C, 67.33; H, 4.58; N, 2.91.
(25 mL) and heated to reflux using water separator for 3 h. The
resulting mixture was cooled to 25–40°C and the solid was
filtered. Further the wet solid was suspended in aqueous 10%
sodium hydrogen carbonate solution (50 mL) and stirred for
30–60 min at room temperature. The resulting precipitate solid
was filtered and washed with water (50 mL) and dried. The crude
solid was purified by crystallization from acetonitrile [21].
(E)-1-(2-(4-Fluorophenyl)-2-oxoethyl)-4-(3-(8-methoxy-2-
oxo-2H-chromen-3-yl)-3-oxoprop-1-enyl)pyridinium
(Z)-6-Ethoxy-2-(pyridin-4-ylmethylene)benzofuran-3(2H)-
one (12)
bromide (7d)
Yield 86%, orange solid, mp 113–115°C, 1H NMR (CDCl3,
500 MHz), 7.56 (d, 1H, H4 coumaranone, J ¼ 8.6 Hz), 6.61 (dd,
1H, H5 coumaranone, J ¼ 8.6 Hz, J ¼ 2.2 Hz), 6.53 (d, 1H, H7
coumaranone, J ¼ 2.2 Hz), 4.1 (q, 2H, OCH2, J ¼ 6.8 Hz), 1.45
(t, 3H, CH3, J ¼ 6.8 Hz), EI-MS m/z (%) 178 (Mþ, 100), 135 (88), 47 (79).
Yield 73%, brown solid, mp 190–192°C, IR ymax/cmꢃ1 (KBr): 1757,
1
–
1715 and 1681 (C O), H NMR (DMSO-d , 400 MHz), 8.99 (d, 2H,
–
6
Ha-pyridine, J ¼ 6.4 Hz), 8.82 (s, 1H, H4 coumarin), 8.54 (d, 2H,
Hb-pyridine, J ¼ 6.4 Hz), 8.20–8.16 (m, 3H, 2H phenyl and Hb
vinylic), 7.87 (d, 1H, Ha vinylic, J ¼ 15.6 Hz), 7.55–7.48 (m, 4H, 2H
phenyl and H5,7 coumarin), 7.40 (t, 1H, H6 coumarin, J ¼ 8.0 Hz),
6.43 (s, 2H, –CH2Nþ), 3.95 (s, 3H, OMe). EI-MS m/z (%) 444 (Mþ, 5),
443 (19), 320 (74), 306 (31), 123 (100), 95 (43). Anal. calcd. for
General procedure for the synthesis of (Z)-4-((6-ethoxy-3-
oxobenzofuran-2(3H)-ylidene)methyl)-1-(2-oxo-2-
phenylethyl)pyridinium halides 13a–e
C26H19BrFNO5: C, 59.56; H, 3.65; N, 2.67. Found: C, 59.32; H, 3.37;
N, 2.90.
To a solution of 12 (1 mmol) in dry acetonitrile (7 mL), different
phenacyl halides 6 (1.2 equiv) and catalytic amount of KI were
added. The reaction mixture was stirred at room temperature for
3–4 days. Progress of the reaction was monitored by TLC. After
completion of the reaction, the solid was filtered off and washed
with acetonitrile to give compound 13. The solids were further
purified if needed by flash chromatography using chloroform/
methanol (99:1) as the mobile phase.
(E)-1-(2-(4-Bromophenyl)-2-oxoethyl)-4-(3-(8-methoxy-2-
oxo-2H-chromen-3-yl)-3-oxoprop-1-enyl)pyridinium
bromide (7e)
Yield 70%, yellow solid, mp 252–254°C, IR ymax/cmꢃ1 (KBr): 1718
and 1676 (C O), 1H NMR (DMSO-d6, 400 MHz), 9.00 (d, 2H,
–
–
Ha-pyridine, J ¼ 6.4 Hz), 8.82 (s, 1H, H4 coumarin), 8.56 (d, 2H,
Hb-pyridine, J ¼ 6.4 Hz), 8.18 (d, 1H, Hb vinylic, J ¼ 16.4 Hz), 7.99
(d, 2H, Ph, J ¼ 8.0 Hz), 7.89 (m, 3H, Ha vinylic and 2H phenyl),
7.55–7.40 (m, H5,6,7 coumarin), 6.45 (s, 2H, –CH2Nþ), 3.95 (s, 3H,
OMe). EI-MS m/z (%) 507 (Mþþ2, 4), 505 (Mþ, 6), 320 (100), 307 (50),
185 (85), 183 (87). Anal. calcd. for C26H19Br2NO5: C, 53.36; H, 3.27;
N, 2.39. Found: C, 53.02; H, 3.51; N, 2.13.
(Z)-4-((6-Ethoxy-3-oxobenzofuran-2(3H)-ylidene)methyl)-
1-(2-oxo-2-p-tolylethyl)pyridinium chloride (13a)
Yield 77%, orange solid, mp 238–240°C, IR ymax/cmꢃ1 (KBr): 1699
1
–
(br, C O), H NMR (DMSO-d , 400 MHz), 9.05 (d, 2H, H -pyridine,
–
6
a
J ¼ 6.4 Hz), 8.61 (d, 2H, Hb-pyridine, J ¼ 6.4 Hz), 7.99 (d, 2H
phenyl, J ¼ 8.4 Hz), 7.78 (d, H, H4 coumaranone, J ¼ 7.8 Hz), 7.49
(d, 2H phenyl, J ¼ 8.4 Hz), 7.25 (s, 1H, H7 coumaranone), 7.09
(s, 1H, H vinylic), 6.93 (d, 1H, H5 coumaranone, J ¼ 7.8 Hz), 6.51
(s, 2H, –CH2Nþ), 4.26 (q, 2H, OCH2, J ¼ 6.4 Hz), 2.46 (s, 3H, CH3)
1.40 (t, 3H, CH3, J ¼ 6.4 Hz). EI-MS m/z (%) 400 (Mþ, 1), 399 (13), 267
(65), 238 (88), 119 (100), 91 (48). Anal. calcd. for C25H22ClNO4: C,
68.88; H, 5.09; N, 3.21. Found: C, 68.72; H, 5.28; N, 3.11.
Representative procedure for the preparation of 6-
ethoxybenzofuran-3(2H)-one (11)
To a mixture of 6-hydroxybenzofuran-3(2H)-one 10 (12 mmol,
1.8 g) and anhydrous potassium carbonate (1 equiv) in 5 mL dry
DMF, ethyl iodide (12 mmol, 1.872 g) was added and the mixture
was stirred under argon for 2 h at 80°C. Water (20 mL) was added
and afterward the mixture was cooled and the mixture was
extracted with ethyl acetate (3 ꢄ 30 mL). The combined organic
extracts were dried over Na2SO4 and the solvent was removed
under reduced pressure. The resulted oil was purified by column
chromatography using petroleum ether/ethyl acetate (60:40) as
the mobile phase to afford compound 11 in good yield [21].
(Z)-4-((6-Ethoxy-3-oxobenzofuran-2(3H)-ylidene)methyl)-
1-(2-(4-fluorophenyl)-2-oxoethyl)pyridinium bromide (13b)
Yield 74%, orange solid, mp 230–232°C, IR ymax/cmꢃ1 (KBr): 1738
1
–
(br, C O), H NMR (DMSO-d , 400 MHz), 9.06 (d, 2H, H -pyridine,
–
6
a
J ¼ 6.4 Hz), 8.61 (d, 2H, Hb-pyridine, J ¼ 6.4 Hz), 8.20–8.17 (m, 2H
phenyl), 7.78 (d, 1H, H4 coumaranone, J ¼ 8.4 Hz), 7.54–7.48 (m,
2H phenyl), 7.22 (s, 1H, H7 coumaranone), 7.10 (s, 1H, H vinylic),
6.93 (d, 1H, H5 coumaranone, J ¼ 8.4 Hz), 6.54 (s, 2H, –CH2Nþ),
4.23 (q, 2H, OCH2, J ¼ 6.5 Hz), 1.40 (t, 3H, CH3, J ¼ 6.5 Hz). EI-MS
m/z (%) 404 (Mþ, 1), 403 (31), 385 (35), 266 (35), 239 (88), 123 (100).
Anal. calcd. for C24H19BrNO4: C, 59.52; H, 3.95; N, 2.89. Found: C,
59.31; H, 3.64; N, 2.57.
6-Ethoxybenzofuran-3(2H)-one (11)
Yield 86%, orange solid, mp 113–115°C, 1H NMR (CDCl3,
500 MHz), 7.56 (d, 1H, H4 coumaranone, J ¼ 8.6 Hz), 6.61 (dd,
1H, H5 coumaranone, J ¼ 8.6 Hz, J ¼ 2.2 Hz), 6.53 (d, 1H, H7
coumaranone, J ¼ 2.2 Hz) 4.61 (s, 2H, CO-CH2), 4.1 (q, 2H, OCH2,
J ¼ 6.8 Hz), 1.45 (t, 3H, –CH3, J ¼ 6.8 Hz), EI-MS m/z (%) 178 (Mþ,
100), 135 (88), 47 (79).
(Z)-4-((6-Ethoxy-3-oxobenzofuran-2(3H)-ylidene)methyl)-
General procedure for the synthesis of (Z)-6-ethoxy-2-
(pyridin-4-ylmethylene)benzofuran-3(2H)-one (12)
6-Ethoxybenzofuran-3(2H)-one 11 (1 equiv), pyridine-4-carboxal-
dehyde (1.4 equiv) and PTSA (1.5 equiv) were suspended in toluene
1-(2-oxo-2-phenylethyl)pyridinium chloride (13c)
Yield 65%, orange solid, mp 214–216°C, IR ymax/cmꢃ1 (KBr): 1726
1
–
(br, C O), H NMR (DMSO-d , 400 MHz), 9.02 (d, 2H, H -pyridine,
–
6
a
J ¼ 6.4 Hz), 8.61 (d, 2H, Hb-pyridine, J ¼ 6.4 Hz), 8.09 (d, 1H, H4
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586
M. Alipour et al.
Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
coumaranone, J ¼ 7.8 Hz), 7.80–7.65 (m, 5H phenyl), 7.21 (s, 1H,
H7 coumaranone), 7.08 (s, 1H, H vinylic), 6.91 (d, 1H, H5
coumaranone, J ¼ 7.8 Hz), 6.51 (s, 2H, –CH2Nþ), 4.25 (q, 2H,
OCH2, J ¼ 6.4 Hz), 1.40 (t, 3H, CH3, J ¼ 6.4 Hz). 13C NMR (DMSO-
d6, 125 MHz), 190.6, 181.3, 168.6, 167.5, 152.6, 148.8, 146.1, 134.7,
133.4, 129.1, 128.2, 127.4, 126.3, 113.7, 112.7, 103.6, 98.0, 65.8,
64.9, 14.2. EI-MS m/z (%) 386 (Mþ, 17), 385 (50), 267 (53), 238 (76),
221 (56), 105 (100). Anal. calcd. for C24H20ClNO4: C, 68.33; H, 4.78;
N, 3.32. Found: C, 68.18; H, 4.53; N, 3.55.
analyzing the docking results. The results were depicted using
Chimera 1.6 [36].
Pharmacology
The capacity of target compounds to inhibit AChE/BuChE was
assessed using Ellman’s method. For this assay, acetylcholines-
terase (AChE, E.C. 3.1.1.7, Type V-S, lyophilized powder, from
electric eel, 1000 units), butylcholinesterase (BuChE, E.C. 3.1.1.8,
from equine serum) and butylthiocholine iodode were purchased
from Sigma–Aldrich. 5,50-Dithiobis-(2-nitrobenzoic acid) (DTNB),
potassium, dihydrogen phosphate, dipotassium hydrogen phos-
phate, potassium hydroxide, sodium hydrogen carbonate, and
acetylthiocholine iodide were provided from Fluka. The target
compounds were dissolved in 10 mL of a mixture of DMSO/
methanol (1:9) and sequentially diluted in phosphate buffer
(0.1 M, pH ¼ 8.0) to obtain desired concentrations. For each
compound, five different concentrations were selected in such a
way to obtain enzymatic inhibition in a range of 20–80%. The rate
of absorbance change was measured at 412 nm for 2 min.
Aliquots of inhibitors (50 mL) were added to assay solution
consisting of phosphate buffer (3 mL, pH ¼ 8, 0.1 M), DTNB
(100 mL, 0.01 M), enzyme (50 mL of 2.5 unit/mL) and pre-incubated
for 10 min and followed by adding substrate (20 mL, 0.075 M).
Assays were carried out with a blank containing all components
except enzyme in order to account for the non-enzymatic reaction.
All experiments were performed at 25°C in triplicate on a UV
Unico double beam spectrophotometer. The reaction rates were
compared to obtain the percent of inhibition due to different
concentrations of inhibitor. IC50 values were determined
graphically from log concentration-percent inhibition curves.
(Z)-1-(2-(3,4-Dihydroxyphenyl)-2-oxoethyl)-4-((6-ethoxy-
3-oxobenzofuran-2(3H)-ylidene)methyl)pyridinium
chloride (13d)
Yield 80%, orange solid, mp 215–217°C, IR ymax/cmꢃ1 (KBr): 3300
1
–
(OH), 1704 (br, C O), H NMR (DMSO-d , 400 MHz), 10.42 (s, 1H,
–
6
OH), 9.71 (s, 1H, OH), 9.01 (d, 2H, Ha-pyridine, J ¼ 6.8 Hz), 8.57
(d, 2H, Hb-pyridine, J ¼ 6.8 Hz), 7.78 (d, 1H, H4 coumaranone,
J ¼ 8.0 Hz), 7.49–7.46 (m, 2H phenyl), 7.22 (s, 1H, H vinylic), 7.08
(s, 1H, H7 coumaranone), 7.00 (d, 1H phenyl, J ¼ 7.6 Hz), 6.93
(d, 1H, H5 coumaranone, J ¼ 8.0 Hz), 6.38 (s, 2H, –CH2Nþ), 4.25
(q, 2H, OCH2, J ¼ 6.8 Hz), 1.40 (t, 3H, CH3, J ¼ 6.8 Hz). 13C NMR
(DMSO-d6, 125 MHz), 188.6, 181.4, 168.7, 167.6, 152.7, 152.3,
148.7, 146.2, 145.7, 127.3, 126.4, 125.1, 121.8, 115.6, 114.9, 113.8,
112.8, 103.7, 98.1, 65.4, 64.9, 14.3. EI-MS m/z (%) 418 (Mþ, 7), 417
(2), 267 (74), 238 (79), 137 (100). Anal. calcd. for C24H20ClNO6: C,
63.51; H, 4.44; N, 3.09. Found: C, 63.30; H, 4.71; N, 3.22.
(Z)-1-(2-(4-Bromophenyl)-2-oxoethyl)-4-((6-ethoxy-3-
oxobenzofuran-2(3H)-ylidene)methyl)pyridinium bromide
(13e)
Yield 75%, orange solid, mp 236–238°C, IR ymax/cmꢃ1 (KBr): 1701
Antioxidant assay
1
In order to evaluate the total antioxidant power of the target
compounds, the FRAP (ferric reducing antioxidant power)
assay [37] was used. This method is based on the reduction of
colorless Fe(III)-TPTZ (2,4,6-Tris(2-pyridyl)-s-triazine) complex to
colored Fe(II)-TPTZ complex by the compounds. To 3 mL of FRAP
reagent (10 mM TPTZ and 20 mM FeCl3 in 300 mM acetate buffer
(pH 3.6)), 100 mL of compounds solution was added and then
incubated at 37°C for 15 min. The change of absorbance was
measured at 585 nm and the concentration of the reduced Fe(II)
was calculated according to the calibration curve of ferrous sulfate
(FeSO4) as standard. The antioxidant activity was expressed as
mmol Fe(II) per gram of dry mass of compounds. Data are the
mean of three independent experiments and are compared to
ascorbic acid as reference.
–
(br, C O), H NMR (DMSO-d , 400 MHz), 9.01 (d, 2H, H -pyridine,
–
6
a
J ¼ 6.0 Hz), 8.61 (d, 2H, Hb-pyridine, J ¼ 6.0 Hz), 8.02 (d, 2H
phenyl, J ¼ 7.8 Hz), 7.91 (d, 2H phenyl, J ¼ 7.8 Hz), 7. 78 (d, 1H,
H4 coumaranone, J ¼ 8.0 Hz), 7.23 (s, 1H, H7 coumaranone), 7.09
(s, 1H, H vinylic), 6.93 (d, 1H, H5 coumaranone, J ¼ 8.0 Hz), 6.49
(s, 2H, –CH2Nþ), 4.25 (q, 2H, OCH2, J ¼ 7.2 Hz), 1.40 (t, 3H, CH3,
J ¼ 7.2 Hz). EI-MS m/z (%) 467 (Mþþ2, 3), 465 (Mþ, 3), 267 (75), 238
(100), 185 (64), 183 (66). Anal. calcd. for C24H19Br2NO4: C, 52.87; H,
3.51; N, 2.57. Found: C, 52.55; H, 3.75; N, 2.38.
In silico docking simulation study
For molecular modeling studies, the docking of target com-
pounds in the active site of AChE was investigated. The pdb
structure of target enzyme (PDB Code: 1EVE) was retrieved from
Protein Data Bank (http://www.rcsb.org/pdb/home/home.do) as a
complex with inhibitor, E2020. Then the water molecules and the
native ligand were removed from the protein structure and
converted to proper pdbqt format with Autodock Tools (ver. 1.5.4)
[33]. The 2D structure of ligands were sketched in MarvineSketch
5.8.3, 2012, ChemAxon (http://www.chemaxon.com), and then
energetically minimized and converted to 3D pdbqt format using
Openbabel version (2.3.1) [34]. Finally, docking simulations were
carried out using Autodock Vina (ver. 1.1.1) [35] in which the
This work was supported by grants from the research council of Tehran
University of Medical Sciences, Iran National Elite Foundation (INEF)
and Iran National Science Foundation (INSF). Molecular graphics and
analyses were performed with the UCSF Chimera package. Chimera is
developed by the 25 Resource for Biocomputing, Visualization, and
Informatics at the University of California, San Francisco.
The authors have declared no conflict of interest.
exhaustive value was set as 80. The other parameters were left as
ꢀ
default values. The three-dimensional box of 40, 40 and 40 A size,
centered at 2.023, 63.29, and 67.062 (x, y, z, respectively) that References
encompassed the active site of AChE, was used to guide the
docked inhibitors within the target enzyme. The lowest energy
conformation of each ligand-protein complex was used for
[1] H. Dvir, I. Silman, M. Harel, T. L. Rosenberry, J. L. Sussman,
Chem. Biol. Interact. 2010, 187, 10–22.
ß 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.archpharm.com

Arch. Pharm. Chem. Life Sci. 2013, 346, 577–587
3-Coumaranone and Coumarin Derivatives as ACE Inhibitors
587
[2] A. Contestabile, Behav. Brain Res. 2011, 221, 334–340.
[3] R. C. de Los, Expert. Opin. Ther. Pat 2012, 22, 853–869.
[4] G. Kryger, I. Silman, J. L. Sussman, Structure 1999, 7, 297–307.
S. Emami Gh. Dehghan, A. Foroumadi, A. Ramazani, A.
Shafiee, Arch. Pharm. Chem. Life Sci. 2011, 344, 588–594. (c) M.
Khoobi, A. Ramazani, A. Foroumadi, H. Hamadi, Z. Hojjati, A.
Shafiee, J. Iran. Chem. Soc. 2011, 8, 1036–1042.
[5] G. Kryger, I. Silman, J. L. Sussman, J. Physiol. Paris. 1998, 92,
191–194.
[20] (a) O. P. Pravin, B. B. Sanjay, D. F. Sandip, K. D. Prashant, T. D.
Shailesh, A. P. Dilip, Bioorg. Med. Chem. 2013, 21, 2434–2450.
(b) C. Brühlmann, F. Ooms, P. A. Carrupt, B. Testa, M. Catto, F.
Leonetti, C. Altomare, A. Carotti J. Med. Chem. 2001, 44 19
3195–3198.
[6] D. Alonso, I. Dorronsoro, L. Rubio, P. Munoz, E. Garcia-
Palomero, M. M. Del, A. Bidon-Chanal, M. Orozco, F. J. Luque,
A. Castro, M. Medina, A. Martinez, Bioorg. Med. Chem. 2005, 13,
6588–6597.
[21] H. Nadri, M. Pirali-Hamedani, M. Shekarchi, M. Abdollahi, V.
Sheibani, M. Amanlou, A. Shafiee, A. Foroumadi, Bioorg. Med.
Chem. 2010, 18, 6360–6366.
[7] P. Camps, X. Formosa, C. Galdeano, D. Munoz-Torrero, L.
Ramirez, E. Gomez, N. Isambert, R. Lavilla, A. Badia, M. V.
Clos, M. Bartolini, F. Mancini, V. Andrisano, M. P. Arce, M. I.
Rodriguez-Franco, O. Huertas, T. Dafni, F. J. Luque, J. Med.
Chem. 2009, 52, 5365–5379.
[22] A. V. Terry, Jr., P. M. Callahan, B. Hall, S. J. Webster,
Pharmacol. Biochem. Behav. 2011, 99, 190–210.
[23] L. Pan, J. H. Tan, J. Q. Hou, S. L. Huang, L. Q. Gu, Z. S. Huang,
[8] M. I. Rodriguez-Franco, M. I. Fernandez-Bachiller, C. Perez, B.
Hernandez-Ledesma, B. Bartolome, J. Med. Chem. 2006, 49,
459–462.
Bioorg. Med. Chem. Lett. 2008, 18, 3790–3793.
[24] P. Kapkova, V. Alptuzun, P. Frey, E. Erciyas, U. Holzgrabe,
Bioorg. Med. Chem. 2006, 14, 472–478.
[9] W. Luo, Y. P. Li, Y. He, S. L. Huang, D. Li, L. Q. Gu, Z. S. Huang,
[25] R. Palin, J. K. Clark, P. Cowley, A. W. Muir, E. Pow, A. B.
Prosser, R. Taylor, M. Q. Zhang, Bioorg. Med. Chem. Lett. 2002,
12, 2569–2572.
Eur. J. Med. Chem. 2011, 46, 2609–2616.
[10] E. Giacobini, R. Spiegel, A. Enz, A. E. Veroff, N. R. Cutler,
J. Neural Transm. 2002, 109, 1053–1065.
[26] J. K. Clark, P. Cowley, A. W. Muir, R. Palin, E. Pow, A. B.
Prosser, R. Taylor, M. Q. Zhang, Bioorg. Med. Chem. Lett. 2002,
12, 2565–2568.
[11] E. Giacobini, Pharmacol. Res. 2004, 50, 433–440.
[12] R. M. Lane, S. G. Potkin, A. Enz, Int. J. Neuropsychopharmacol.
2006, 9, 101–124.
[27] M. Alipour, M. Khoobi, A. Foroumadi, H. Nadri, A. Moradi, A.
Sakhteman, M. Ghandi, A. Shafiee, Bioorg. Med. Chem. 2012,
20, 7214–7222.
[13] Y. Furukawa-Hibi, T. Alkam, A. Nitta, A. Matsuyama, H.
Mizoguchi, K. Suzuki, S. Moussaoui, Q. S. Yu, N. H. Greig, T.
Nagai, K. Yamada, Behav. Brain Res. 2011, 225, 222–229.
[28] S. Khode, V. Maddi, P. Aragade, M. Palkar, P. K. Ronad, S.
Mamledesai, A. H. Thippeswamy, D. Satyanarayana, Eur. J.
Med. Chem. 2009, 44, 1682–1688.
[14] A. Skrzypek, J. Matysiak, A. Niewiadomy, M. Bajda, P.
Szymanski, Eur. J. Med. Chem. 2013, 62C, 311–319.
[15] J. S. da Costa, J. P. Lopes, D. Russowsky, C. L. Petzhold, A. C.
Borges, M. A. Ceschi, E. Konrath, C. Batassini, P. S. Lunardi,
C. A. Goncalves, Eur. J. Med. Chem. 2013, 62C, 556–563.
[29] F. Belluti, A. Rampa, L. Piazzi, A. Bisi, S. Gobbi, M. Bartolini, V.
Andrisano, A. Cavalli, M. Recanatini, P. Valenti, J. Med. Chem.
2005, 48, 4444–4456.
[16] M. Catto, L. Pisani, F. Leonetti, O. Nicolotti, P. Pesce, A.
Stefanachi, S. Cellamare, A. Carotti, Bioorg. Med. Chem. 2013,
21, 146–152.
[30] H. Pajouhesh, G. R. Lenz, NeuroRx. 2005, 2, 541–553.
[31] M. A. Lovell, W. R. Markesbery, J. Neurosci. Res. 2007, 85, 3036–
3040.
[17] S. Starcevic, P. Kocbek, G. Hribar, T. L. Rizner, S. Gobec, Chem.
Biol. Interact. 2011, 191, 60–65.
[32] W. R. Markesbery, M. A. Lovell, Arch. Neurol. 2007, 64, 954–956.
[33] M. F. Sanner, J. Mol. Graph. Model. 1999, 17, 57–61.
[18] a) H. A. Stefani, K. Gueogjan, F. Manarin, S. H. Farsky, J.
Zukerman-Schpector, I. Caracelli, S. R. Pizano Rodrigues,
M. N. Muscara, S. A. Teixeira, J. R. Santin, I. D. Machado, S. M.
Bolonheis, R. Curi, M. A. Vinolo, Eur. J. Med. Chem. 2012, 58,
117–127. b) J. Liu, F. Wu, L. Chen, L. Zhao, Z. Zhao, M. Wang,
S. Lei, Food Chem. 2012, 135, 2872–2878. c) R. G. Kalkhambkar,
G. M. Kulkarni, C. M. Kamanavalli, N. Premkumar, S. M.
Asdaq, C. M. Sun, Eur. J. Med. Chem. 2008, 43, 2178–2188.
[34] N. M. O’Boyle, M. Banck, C. A. James, C. Morley, T.
Vandermeersch, G. R. Hutchison, J. Cheminform. 2011, 3, 33.
[35] O. Trott, A. J. Olson, J. Comput. Chem. 2010, 31, 455–461.
[36] E. F. Pettersen, T. D. Goddard, C. C. Huang, G. S. Couch, D. M.
Greenblatt, E. C. Meng, T. E. Ferrin, J. Comput. Chem. 2004, 25,
1605–1612.
[37] I. F. Benzie, J. J. Strain, Anal. Biochem. 1996, 239, 70–76.
[19] a) M. Khoobi, A. Foroumadi, S. Emami, M. Safavi Gh.
Dehghan, B. H. Alizadeh, A. Ramazani, S. K. Ardestani, A.
Shafiee, Chem. Biol. Drug Des. 2011, 78, 580–586. (b) M. Khoobi,
[38] X. L. Ma, C. Chen, J. Yang, Acta Pharmacol. Sin. 2005, 26, 500–
512.
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